Comparison of Ethanol Concentrations in Saliva and Blood

Abstract

ABSTRACTAlcohol concentrations in blood and saliva were compared on the basis of 74 experiments, in which 38 volunteers took part. They received a dose of ethanol of 0.7 g/kg of body weight (men) and 0.6 g/kg of body weight (women). Duplicate venous blood samples and an unstimulated mixed saliva secretion were taken simultaneously at 15-minute intervals up to 5 hours. The study shows good agreement between alcohol concentrations in both specimens. In over 50% of the results, the difference did not exceed ± 0.05 g/L, and in over 75%, 0.1 g/L. The mean value of the difference did not differ statistically significantly from zero (mean = 0.020 ± 0.089 g/L, median = 0.00 g/L). The Pearson's correlation coefficient amounted to 0.94 (p<0.0001). The difference between the mean ethanol concentration in blood and saliva was relatively high only for the samples collected during the first hour after consumption. After that, the difference did not exceed 0.05 g/L. The shapes of time profiles of alcohol concentration in blood and saliva were different, because saliva alcohol concentration (SAC) is proportional to arterial blood alcohol concentration. The mean value of blood to saliva alcohol concentration ratio (BAC/SAC) amounted to 0.978 ± 0.174, and the median was 0.980. In the authors' opinion saliva analysis for alcohol can be helpful in the assessment of a driver's sobriety.